Lubricating oils



atented May 9, 1939 UNITED STATES LUBRICATING one No Drawing. Application June 4, 3.932,

. Serial N9 15,432

Our invention relates to improvements in lubricating oils and more particularly to lubricating oils having a high film strength endincreased lubricating qualities.

It is well known that mineral lubricating oils are deficient in oiliness characteristics, which is the most importantcharacter of the lubricant when used under conditions of boundary lubrication where the viscosity of the lubricant plays little or no part in lubrication. It is also well known that mineral oils have a very low film strength and have a tendency to break down and allow seizure of the rubbing surfaces when the pressure of rubbing at the point of contact reaches a relatively low value. These two factors are of great importance, in present clay lubrication of machinery, The very best lubricents on the market are deficient in these characteristics and the object of this invention is to provide a lubricant with greatly reduced coeficient of friction and much higher film strength, the many advantages of which are fully appreciated by those skilled in the art of menuiacturing and using lubricants.

25 The use of animal and vegetable oils to overcome these objections introduces other objec- .tionable characteristics to the lubricant, such as gumming, polymerization, high acidity, ob-

jectionable-odor, and high manufacturing costs.

Substituting fatty acids, such as oleic and the like, for the animal and vegetable oil is an im-- provement over the prior art, but unsaturated fatty acids have a tendency to polymerize and sludge in use and the saturated fatty acids are not fully soluble in the mineral lubricant, causing them to settle out in cold weather. over, saturated and unsaturated fatty acids do not improve the film strength of the resulting lubricant. However, the fatty acids will lower 343 the coefilcient of friction of the lubricant under boundary lubrication conditions, and it is defi 'nitely established that the carboxyl group at the end of the fatty acid molecule plays a very important role in this friction reduction. The fatty acid may accomplish this beneficial action -due to its acidic character or because of its polar character, Irrespective of the theory involved, a substance to lower the coeilicient of friction should have an active point in the molecule.

One object of our invention is to increase the film strength of mineral lubricating oils.

Another object of our invention is to provide.

More

(Cl. biz-=9) Gther objects of our invention will appear from the following description.

We have discovered methods by which mineral lubricants can be produced having very low coefllclents of friction and very high film strength. 5 Original mineral lubricants of high quality are greatly improved and poor quality original lubricants can be made satisfactory and usable by our invention. This is of particular importance since) these beneficial results are easily and w cheaply accomplished. The raw materials required are plentiful and cheap, and only very small percentages of the substance made are required in mineral lubricating oils.

-In practicing our invention we first halogenate an organic fatty acid. The saturated and unsaturated fatty acids are easily halogenated. In the case oi unsaturated acid the halogen enters the molecule at the point of unsaturation by ordinary addition. Further halogenation is by substitution of halogen for hydrogen, resulting in the evolution of hydrogen halide. With the saturated acids, all the halogen atoms are added by substitution. All degrees of halogenation are contemplated in this invention. After halogenating the organic fatty acid to the required degree, any excess halogen or hydrogen halide dissolved or otherwise present in the reaction product is removed by any of the ordinary means giving a halogenated fatty acid for the second so step of the process. It should be stated that the crude commercial fatty acids are entirely satisfactory for this process as the impurities present do not have any objectionable influence on the process.

The thus prepared halogenated acid is blended with aromatic hydrocarbons either directly or in solution with any of the inert organic solvents. To this mlxtureiinely divided anhydrous aluminum chloride is added, which causes the aro- 4o matio hydrocarbon and the halogenated acid to combine into one moleculewith the evolution of hydrogen halide by the reaction commonly referred to as Friedel-Crafts, which has been thoroughly described in chemical literature and 45. needs no further explanation. With proper mo lecular quantities of the various constituents, and after sufllcient time has elapsed; all of the halogen in the fatty acid molecule will be substituted by the aromatic radical. In addition, this invention contemplates adjusting the molecular quantities of the constituents, the time and reaction temperature to obtains. crude reaction product consisting of a halogen and aromatic radical substituted fatty acid. The degree of action with aluminum chloride.

original halogenation and the number of halogen atoms and aromatic radicalsin the finished product may vary over a wide range depending upon the characteristics required in use of the finished.- product.

After completing the above reaction, the solvent, if any, is used; is removed; and the product may be used immediately'after settlingv or filtering out any sludge formed during the re- Further the product may be purified" by low temperature, low pressure distillation or by extraction with selective solvents. The product may be diluted with a suitable solvent to facilitatesludge settling.

The finished product is a stable compound and very efficient in accomplishing the objects of this invention when used in small quantities.

As an example of this invention, ordinary commercial stearic acid with a melting point of about 120 F. to 140 F. was chlorinated direct with chlorine until the chlorinated product had a cold test of about '60 F. Two other batches were chlorinated-one toa cold test near 0 F., and the other to a cold test of approximately 100 F. To 100 grams of the F. cold test chlorinated acid in petroleum naphtha solution, 15 grams of naphthalene were added at room. temperature. On

' warming this mixture, the naphthalene went into 30 solution. To this solution about 15 gramsof anhydrous aluminum chloride was slowly added. The reaction was conducted in an open container, and the hydrogen chloride released by the reaction was substantially removed as formed; The reaction may be carried out at room temperature over a long period of time, or by using elevated temperatures (say 140 F. to 160 F. or above) the reaction is much more rapid. When the reaction is completed the resulting product should be heated to around 200 F. to release free hydrogen chloride. Ifno solvent is used with the original reacting substances, a solvent may be added at this stage to facilitate settling of the aluminous sludge. In either case the diluent is removed by distilling'ofl at low temperatures and high vacuum; the residual product of the distillation may be recovered direct or may be distilled overhead.

More or less naphthalene would have been used with the higher and lower melting point halogenated acids, but not necessarily proportional amounts. The amount of anhydrous'aluminum chloride added is varied with the amount of aromatic compound added, and the character of the desired finished product. 7 If purification of the final product is by distillation, low pressure vacuum distillation should be employed.

The product prepared and purified as shown above was added to a high quality lubricant which had a coefficient of friction of 0.135 when tested veloped by Dr. W. H. Herschel of the United States Bureau of Standards) and a film strength of only 10,500 pounds per square inch when tested on the Tirnken machine (a machine developed by the Timken Roller Bearing Company). 0.25% of the product of this invention in the above lubricant gave a Herschel coefficient of friction of 0.071 or practically only half as great friction as I the original oil showed. 0.25% of 'the product of this invention in the above mineral oil lubricant gave a product with a film strength of 22,000 pounds per square inch when tested on the Tlmken machine, or more than double the;

film strength'of the original lubricant.

by the Herschel Friction Testing machine (de- With poorer quality original mineral oil lubricants, larger quantities of the product of this invention would be required to accomplish the same degree of improvement. These quantities may run as high as 3% or more.

In another example of this invention, benzene was used instead of naphthalene with considerable success. Any of the aromatic hydrocarbons or substituted aromatic hydrocarbons are suitable for use in this invention, such as toluene, xylene, etc. and anthracene, phenanthrene and their substitution products, and other benzene radical substitution products which are reactive in the Friedel-Crafts reaction, including natural products rich in aromatic hydrocarbons.

Organic fatty acids referred to in the specifications and claims include all natural organic acids, synthetic organic acids and the long chain fatty acids as obtained by .any of. the oil 'saponification processes or by synthesis. The commercial fatty acids are, as a rule, mixtures of different fatty acids, and such mixtures are included in the term organic fatty acids.

The product of this invention may be prepared by reactions other than the Friedel-Crafts'. For example, halogenated fatty acids and halogenated aromatic hydrocarbons may be combined to form like products by condensing agents such as strong alkalies, alcoholates, metallic substances, alkali amides and the like, by well known chemical reactions.

It will be understood that certain features and sub-combinations are of utility and may be employed without'reference to other. features and sub-combinations. This is contemplated by and is within the scope of our claims. It is further obvious that various changes may be made in details within the scope of our claims without departing from the spirit of our invention. It is, therefore, to be understood that our invention is not to be limited to the specific details shown and described.

Having this described our invention, what-we claim is:

1. A lubricating oil comprising in combination a mineral oil and a small percentage of a halogenated fatty acid aromatic hydrocarbon halogeniferous condensation product.

2. A lubricating oil comprising in combination a hydrocarbon oil and a small amount of a halogeniferous condensation product \selected from the following group: a halogenated organic acid-aromatic hydrocarbon condensation product; a chlorinated fatty acid-aromatic hydrocarbon condensation product; a chlorinated aromatic hydrocarbon-organic acid condensation product; a chlorinated aromatic hydrocarbonchlorinated fatty'acid condensation product; .a chlorinated, fatty acid-aromatic hydrocarbon condensation product.

3. A lubricating oil comprising in combination a hydrocarbon oil and a small amount of a halogeniferous condensation product derived by condensinga halogenated organic acid with an aromatic hydrocarbon.

4. A lubricating oil comprising in combination a hydrocarbon oil and a small amount of a halogeniferous condensation product derived by condensing an organic acid with ahalogenated aromatic. hydrocarbon.

v 5. A lubricating oil comprising in combination condensing a chlorinated organic acid with an a hydrocarbon oil and a small amount of a aromatic hydrocarbon. halogeniferous condensation product derived by A lubricating 011 comprising in combination condensing a chlorinated fatty acid with an arohydrocal'mn and a small ammmt of a 9 math, hydmcarbom halogenii'erous condensation product derived by 5 6. A lubricating oil comprising combination condensing an organic acid with a chlorinated a hydrocarbon oil and a small amount of a aromatic hydrocarbon halogenii'erous condensation product derived by A lubricating 011 comprising in cembmauon condensing a halogenated fatty acid with a halhydrocarbon and a Small amount of a w halogeniferous condensation product derived by m Ogenated hydrocarbmv nd nsin a chlorinated fat cid with a chlo- 7. A lubricating 011 comprising in combination ff z hygdm'carbom W a a hydrocarbon oil and a small amount of a ERT H. LINCOLN.

halogeniferous condensation product derived by ALFRED HENRIKSEN. 

